Positive tool orientation significantly improves data quality and enables gravity descents of wireline tool-

strings to extreme deviations

Martin LeonardPetromac Technical Manager

Wireline Data Acquisition

Accurate and Efficient

Plagued by Mechanical Limitations• Ledging/Washouts/Cuttings• Deviation• Differential Sticking

✓

Wireline Logging Options

Logging Ledges Deviation Sticking Quality Sampling $ rig time

Wireline

Pipe Conveyed (PCL)

Tractor

Through Drillpipe

LWD

WL Conveyance System

Conveyance Sys & Tractor

Petromac

Centre of gravity

Rotational centre

logging

tool

• Orients the Guide upwards

• Aligns toolstring sensors on way in the hole, allowing data to be captured during down-log

• Prevents image rotational tracking

• Quicker / Improved fluid samples & pressures as taken from the high, undamaged, side of the wellbore

• Cores can be cut parallel to the bedding planes-valuable for core permeability measurement

Tool Taxi is stable sitting on it’s wheels, where centre of

gravity is lowest

Importance of Orientation

Alignment of Tool Sensors

• NMR data acquired in previous well in the same field was unusable• Orienting NMR with wheels yielded excellent data

SPE-192876-MS

SPE-192876-MS

Tool Centralization

• Traditional centralizing techniques result in high drag and stick-slip

• Centralizing using wheeled carriages results in low drag and excellent data quality

Formation Sampling - Permeability

Lowside vs Highside

• In deviated wells the weight of the drill pipe is borne on the low side of the wellbore:• Suspended cuttings are ground into the pore spaces• Drill pipe scours the sealing mud-cake from the wellbore wall,

thereby allowing repeated invasion of drilling fluids

• Sampling from the high side of the wellbore results in faster clean-up from improved permeability and less invasion

Formation Sampling – Sealing

• Probe packers are designed to match the curvature of the borehole and achieve the best seal when aligned perpendicular

• In deviated wells, tool will tend to ride on its side, which can create sealing problems

• Oriented sampling ensures excellent sealing

Oriented Coring

• In deviated wells, horizontal cores from the side of the wellbore are cut parallel to the bedding planes, rather than through them, which have more value for core analysis.

• Ability to core without any interference with the stress cage

Cores cut parallel to bedding planes.

Petromac

Tool 64 Deg

Taxi 77 Deg

Gen3 Taxi 82 Deg

Tool Drag

• 79° Deviation – ADNOC Offshore, UAE• 78° Deviation – B&W Energy, Gabon• 75° Deviation – Formation Sampling String – HESS, Malaysia

• Above these deviations, reduction in the Tool Drag, allows longer and deeper tractor operations

Conclusions

Current logging technology is Risk Mitigation

- Increase Power

Focus should be on Risk Prevention

- Positive Tool Orientation